The invention is directed to encrypting and decrypting blocks of digital data, more specifically, to a cipher method and device for the block-by-block conversion of a first digital block into a second digital block using at least one freely selectable control block.
The rapidly growing use of digital communication systems in commerce has spurred the need for cryptographic systems which are secure against popular "cryptoanalysis" or cracking techniques at least for a sufficient length of time. Prior art systems such as Massey, et al. U.S. Pat. No. 5,214,703 use a block cipher device which is suitable both for the encryption of plain text blocks and for the decryption of ciphertext blocks. However, prior art systems cannot be designed with any input/output size by appropriately scaling the size of system operations and are susceptible to existing cracking techniques. In addition, use of this cryptographic apparatus guarantees that any communications equipment will be interoperable only if all are using this same cryptographic apparatus.
Accordingly, it is an object of the present invention to provide a novel scaleable block cipher device.
It is another object of the present invention to provide a novel block cipher device which overcomes the disadvantages of the prior art.
It is yet another object of the present invention to provide a novel method of converting an initial block to a final block for use in encrypting and decrypting digital communications.
It is still another object of the present invention to provide a novel block cipher device having multiple stages which is suitable for encrypting and decrypting digital information.
It is a further object of the present invention to provide a novel method for use in encrypting and decrypting information which minimizes the possibility of signal interception.
It is yet a further object of the present invention to provide a novel block cipher device which is scaleable and customizable.
It is still a further object of the present invention to provide a novel block cipher device which is not vulnerable to standard cryptoanalysis techniques.
These and many other objects and advantages of the present invention will be readily apparent to one skilled in the art to which the invention pertains from a perusal of the claims, the appended drawings, and the following detailed description of the preferred embodiments.